Analysis On Slope Prevention And Stability Detection Of Longmenhao Primary School On Reconstructed Tushan Road

With the development of our economy and acceleration of urbanization, urban road traffic facilities have fundamental and leading functions to urban economy and social development as an important infrastructure in the city. For the purpose of constructing economical society, improving urban living environment and promoting sustainable development of cities, it is necessary to develop urban public transport. However, all subway lines under construction or in planning at present cross the downtown area where all types of viaducts, pedestrian overcrossings, high-rise buildings, underground pipelines and existing buildings have been constructed. The newly built subway inevitably crosses bridges, roads, buildings and mountains. Construction certainly has influences on the stability of neighboring buildings and structures whether shallow tunneling method or shield driven method is utilized to do pit excavation. Therefore the important task is to guarantee the safety of existing bridges, buildings and pipelines and reduce their risk of being influenced by pit excavation. This needs urgent solution. While it is a common phenomenon that pit excavation process of railway transport greatly influences the stability of neighboring buildings on the slope. Blind excavation of pit and slope without sufficient analysis easily results in deformation and damage of neighboring buildings and underground structures. Relevant specifications at present do not have definite regulations telling us the influences of pit excavation on stability of neighboring buildings. Basic specification just refers to strip and rectangular constructions on the top of stable slope. It stipulates horizontal distance between edge and top of building foundation. There is not description about othe types of slopes and constructions. Research on pit excavation, slope and construction is less. Further study needs doing on the stability of construction foundation under coupled effect of them three. Engineering background of this paper is the influence of Chongqing east gate bridge south interchange project namely Tushan Road reconstructed project on the stability of neighboring Longmenhao Primary School. It does comparative analysis on slope stability of Longmenhao Primaiy School utilizing on-site investigation, theoretical analysis and physical monitoring. Research work and main conclusions are as follows.1.Through research analysis, it is seen that Longmenhao Primary School on slope excavation section is frame structure whose inside foundation is strip foundation, outside foundation is pile foundation and bearing stratum is bedrock;2.Computational analysis on stability of strong weathered layer and medium weathered layer tells that upright excavation results in instability of the slope. In order to ensure the safety of teaching building on the top, engineering management should be done on this slope. Cutting slope excavation would be done after it becomes stable;3.According to exploration results, slope failure mode is strong weathering rock slipping along strong and medium weathering interface polyline. Sliding force is so high that it is not suitable to use the original rib plate anchored bolt retaining way. This paper proposes relevant preventing measures;4.According to geological exploration data and slope management scope, design uses anchor pile retaining wall to retain and protect it. Protective guard and intercepting dike are set on the top of pile. Pile-plank retaining wall is divided into four types on the basis of sliding force, free face height and rock-socketed condition;5.Construction monitoring of slope after management should be done in each typical slope section. Observational network including no less than 3 observation points would be set on the top of retaining structure. Utilize theodolite, level and surface displacement extensometer to monitor displacement, movement speed and direction. Surface fissure monitoring range is within 40m on slope top.6.Through analyzing monitoring data, it is known that accumulated maximum horizontal displacement of Longmenhao Primary School slope does not exceed warning value, change rate of horizontal displacement for continuous days does not exceed the warning value and change rate of cumulative settlement does not exceed warning value these days. Slope settlement and horizontal displacement outside teaching building tend to be stable. Slope settlement and horizontal displacement of upward side of tunnel being in the position of kindergarten are also of stability. Settlement and horizontal displacement of deep foundation pit top in the position of tunnel trend towards stable. Variation amplitude of displacement in deep part of slope is low. Slope is basically stable. It is suggested to be continually monitored.